Abduction-type motor and fabrication method of motor stator thereof

ABSTRACT

In an abduction-type motor having a divided core  5  (a-l) formed by dividing a stator core into plural blocks and a motor stator having such a structure as the divided core may be reassembled, the motor has a coil winding frame  6  continuously formed a continuous unit of coupling parts, a part of which is flexible and made of insulation material, embedded into the individual divided cores, and a coil  7  arranged and wound by supporting the divided core so that the teeth top parts of the divided core may be directed inside and located on a circle, in which its coil winding structure has the number of coil stages at the teeth top part (external peripheral part) of the divided core larger than the number of the coil stages at the internal peripheral part, and the diameter of the teeth top part of the divided core after assembly is identical to the diameter of the teeth top part while coil winding work, and the length of the crossover line  7   s  between the coil windings is made enough to be equivalent to a single slot or more, not excessive or not insufficient.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 10/231,477,filed on Aug. 30, 2002.

BACKGROUND AND SUMMARY OF THE INVENTION

This application claims the priority of Japanese Application No.2002-41290, filed Feb. 19, 2002, the disclosure of which is expresslyincorporated by reference herein.

The present invention relates to an abduction-type motor such as drivemotor for information devices, fan motor and disk drive motor and to afabrication method of its motor stator.

Generally the fabrication of an abduction-type motor involves simplecoil winding machine work in order to obtain high-density coil windings.However, recent requirements include coil winding with even higherdensity in order to downsize the motor and increase its efficiency. Inorder to meet this requirement, and to enable the stator structure toincrease the occupied coil volume, a divided type stator is used whichhas its core divided into several parts, each corresponding to theindividual poles and with the stator being fabricated after the coilwinding work.

Japanese Patent Laid-Open Number 2000-152528 is an example of a priorart abduction-type motor with a divided stator core. In this method, thedivided cores are linked together with thin magnetic material at theheads of the teeth parts of the individual divided cores, and the cores,which are die-cut in a rectilinear shape, are assembled in a circleafter the coil winding work. Then, the single end part is fastened. Inthis example, the final step is completed by fastening the single endpart by using the coupling pin, which may be fixed alternately bywelding work.

Since the magnetic poles are connected by magnetic materials in theabove prior art, magnetic flux leakage may occur between the magneticpoles and the efficiency of the motor may be significantly reduced.Though the machine-wound operation can be applied by machines for theindividual divided cores at the coil winding work, the finishing workfor the end part of the individual coil winding is required instead offinishing the end part of the entire continuous coil line. It isespecially required to wind a set of coils for an identical phase at thedivided cores separated away from one another in a multi-phase andmulti-pole machine, and in this example, the finishing work for the coilwinding is required for the individual divided core, which requires anextended period of time.

An example of the coil winding is shown in FIG. 2. In this example, thestator core 5 having 12 poles is shown, and in case of applying the coilwinding work with the coil 2 for the single phase (corresponding to fourpoles) at the divided core, it is assumed is such a method, as shown inFIG. 2(a), that four poles are made supported in a circumferentialdirection by the support tool for the coil winding work, applied by thecoil winding machine flyer 31. When the length of the crossover line islonger or shorter than the designated line length, this method can beonly applied to the motor in which four coils are arranged uniformly at90° positions. For example, as the coil arrangement for 10 poles and 12slots is thus shown in FIG. 2(b), the excessive length arises at thecrossover line between adjacent coils, and thus the insufficient lengtharises at the crossover line between coils with rotational symmetry.Thus, it is one of problems to be solved in coil winding to reduce theexcessive and/or insufficient length of the crossover line.

In addition, when fabricating the divided cores, it is important tofabricate the divided cores so as to prevent the wound coils frominterfering one another. In case of applying the coil winding methodshown in FIG. 2(a), the line extended between the start point and theend point for the wound coil is located inside the inner diameter of thecore. This is because the coil winding work is performed while thetension applied during the coil winding work is directed inside theinner diameter, which causes the irregular coil outline even if thestart point and the end point of the coil are forced to be located inthe direction toward the outside diameter, and ultimately the occupiedvolume of the coil is reduced.

An object of the present invention is to provide a high-efficiency andsmall abduction-type motor and a fabrication method of its motor statorwhereby the stator core is divided, the coil winding work is applied tothe divided cores with higher occupied volume, and the stator core,including the coil windings, is configured to be easily reassembled sothat the finishing work for the end part of the individual coil windingmay be eliminated and a continuous machine-wound is formed.

In order to solve the above problems, in an abduction-type motor havinga divided core formed by dividing a stator core into plural blocks, anda motor stator having such a structure as the divided core may bereassembled, the motor has a coil arranged and is wound by supportingthe divided core so that the teeth top parts of the divided core aredirected inside and located on a circle, and the lead lines for thestart of the coil winding and the end of the coil winding are arrangedat the teeth top parts.

In the coil winding structure of the divided core, the number of coilstages, for the teeth top parts of the divided cores located outside, ismade larger than the number of coil stages for the inside parts.

The diameter of the teeth top part of the divided core, after assembly,is identical to the diameter of the teeth top part of the divided coremaintained during the coil winding work, and the finished coil windingis so formed as to have an adequate pressure extended length for asingle slot.

The stator core has a coil winding frame formed as a series of units,each coupled at the coupling parts made of insulation material andembedded into the individual divided core, a part of which can beflexibly bent.

In the assembly method of the abduction-type motor having a divided coreformed by dividing the stator core into plural blocks with its teeth topparts arranged in the direction to the outside and having such astructure as to be reassembled with said divided cores, the motor statoris assembled by means of a coil winding frame formed as a series ofunits. Each unit is coupled by coupling parts made of insulationmaterial and embedded into the individual divided core, a part of whichcan be flexibly bent. The coupling parts of the coil winding frame aredeformed and arranged during the coil winding work so that the teeth topparts of the divided core may be arranged on a hypothetical circle anddirected to its inside. The coil winding work is applied continuously tothe divided cores, and the coupling parts of the coil winding frame isdeformed after the coil winding work, so that the teeth parts of thedivided core may be directed to the outside.

According to the present invention, since the abduction-type motor isstructured so that its stator core may be formed as a set of divided andcoupled units, and its coupling part makes it possible to reassemble thedivided units easily, it will be appreciated that a continuousmachine-wound work can be realized without processing the cableterminals of the coil windings, and that a high-efficiency andsmall-sized abduction-type motor can be realized.

In addition, as the continuous coil winding work is enabled by directingthe teeth top parts of the divided cores outside and arranging them on ahypothetical circle at the coil winding work, and the stator core isassembled by transforming the divided cores at the center of theengagement part of the coil winding frame after the coil winding work sothat its teeth top parts may be directed inside, the length of theindividual crossover lines between the divided cores when arranging theteeth top parts so as to be directed outside and located on thehypothetical circle at the coil winding work can be almost identical tothe necessary length of the individual crossover lines after theassembly process, and thus, it will be appreciated that the terminalprocess for the coil cable at the assembly process can be eliminated.

As the teeth top parts of the divided cores are arranged inside and thenumber of coil stages for the teeth top parts of the divided cores(located outside) is made larger than the number of coil stages fortheir inside parts, which leads to the optimum arrangement of thecrossover lines at the teeth top part, that is, the circumferential partof the cores assembled as the stator core, for the start of the coilwinding and the end of the coil winding, it will be appreciated that theinterference between the coils at the assembly process can be avoided.

In addition, as the continuous machine-wound work without any coilwinding work can be realized, it will be appreciated that the structurefor assembling the divided cores while their crossover lines beingconnected can be realized and the freedom of the core shape can beextended. As the magnetic material is not used near the teeth parts ofthe divided cores, it will be appreciated that the magnetic leakagebetween the teeth can be avoided and thus the efficiency can beincreased. And furthermore, as a single unit is assembled in the coilwinding frame with the insulation part, it will be appreciated that theeasy assembly process can be established and that a small-sized andlow-cost abduction-type motor can be realized.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a schematic diagram illustrating the stator core of thebasic abduction-type motor and the coil winding structure in oneembodiment of the present invention;

FIG. 2(a-b) details the conventional method for winding a coil in thedivided core;

FIG. 3(a-d) illustrates the coil winding frame having engaging partslinked to one another and the relation between the divided core and thecoil winding frame;

FIG. 4 illustrates an example of the structure in which the coil windingframe of the invention is installed in the divided core and the top ofthe teeth parts is made directed inside and arranged on a circle;

FIG. 5 illustrates an example of the structure in which the coil windingframe of the invention is installed in the divided core and the top ofthe teeth parts is made directed outside and arranged on a circle;

FIG. 6 illustrates an example of the structure in which the coil windingframe of the invention is installed in the divided core and the coilwinding work is applied while the teeth parts are made directed insideand arranged on a circle;

FIG. 7 is a cross-sectional drawing illustrating the state of the corewith a coil wound assembled as the motor stator;

FIG. 8 illustrates the process of applying a continuous coil windingwork and the coil winding method;

FIG. 9 illustrates the shape of the coil-wound stator core and itsassembly process in the motor stator; and

FIG. 10 is a structural drawing of the motor illustrating an example ofthe structure of the abduction-type motor of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a schematic diagram illustrating the structure of thestator core of the basic abduction-type motor in one embodiment of thepresent invention. The stator core is so structured as to be dividedinto plural divided cores 5 divided in the circumferential direction inthe abduction-type motor, in which the convex-shaped engage parts 5-2are formed in the individual inside peripheral side of the divided cores5, and the individual divided cores 5 are fixed by means that theconcave-shaped engage parts 5-3, enabled to be engaged with the engageparts 5-2, are formed at the stator support members 8 shaped in acylinder to be arranged at the inside peripheral of the divided core 5.The rotor which is not shown is arranged around the stator of theabduction-type motor and this rotor has a rotary yoke and a permanentmagnet.

In this embodiment, what is shown is an example of an arrangement forthree-phase, ten-pole and twelve-divided core parts (5 a to 5 l), andten arc-type magnets (not shown). The divided core 5 is divided into 12parts, and the coil winding frames 6 individually insulated are arrangedin a single divided core 5 as shown in the figure, and then, the coilwinding (coil) 7 is made wound at the coil winding frame. Twelve dividedcores 5 are assigned to the individual three phases, A, B and C, inwhich A-phase is defined by the cores 5 a and 5 b and the 5 g and 5 harranged diagonally, B-phase is defined by the cores 5 c and 5 d and thecores 5 i and 5 j, and C-phase is defined by the cores 5 e and 5 f andthe cores 5 k and 5 l, thus, the individual phase corresponds to fourdivided cores 5, respectively.

The coil winding frame 6 is bonded at the coupling part a as shown inthe figure, and it is so configured as to be deformed with respect tothe coupling part as the base point.

Now, referring to FIGS. 3(a-d), the coil winding frame 6 is described indetail. The identical numbers are assigned to the identical parts tothose in FIG. 1.

As shown in FIG. 3(a), coil winding frames 6 are coupled at the couplingparts a excluding the both end parts. As shown in the magnified view ofFIG. 3(b), the single coil winding frame is composed of the teeth-sideframe 6-1, the intermediate frame 6-2, the engagement-side frame 6-3 andthe coupling part a, in which, as shown in the magnified view of thedetail cross-sectional view, the coupling part a is made as thin-walledmember and flexible in the vertical direction in the figure. In otherwords, the coil winding frame 6 which is formed as a series of units,each coupled at the coupling parts made of insulation material, a partof which can be flexibly bent, can be bent up and down.

FIG. 3(c) shows the relation between the divided core 5 and the coilwinding frame 6. This figure is a perspective view of the single unit ofthe coil winding frames 6 and the divided core 5 to be engaged into oneof the coil winding frames 6, and FIG. 3(d) is an assembly drawing forinstalling the divided core 5 into the coil winding frames 6 withadjacent frames coupled continuously. As found in the figures, thedivided core 5 has a teeth part 5-1 and an engagement part 5-2, and thewidth of the top of the teeth part 5-1 is made wider where the magneticfield generated by the rotator (not shown) can be detected soefficiently as to be able to make the best use of the magnetic field.The engagement part 5-2 is shaped in a reverse taper in order to supportthe stator by the stator support member 8 (in FIG. 1) engaged with theengagement part so as to endure the motor torque and prevent theengagement part from being pulled out due to the centrifugal force. Inaddition, as found in the figures, the coil winding frames 6 are dividedinto two parts, 6 and 6′, in the longitudinal direction at the centerline of the side wall of the frame.

Thus, after the divided cores 5 are supported by the series coil windingframes 6 and 6′, they are arranged in a single line as shown in FIG.3(a). The coil winding frame 6 can be formed by insert molding with thedivided cores 5 arranged, and it will be appreciated in the insertmolding that the mechanical precision of the individual parts of thecoil winding frame 6 can be increased.

FIG. 4 shows an example of the circular arrangement for facilitating thecoil winding work. The identical numbers are assigned to the identicalparts to those in FIGS. 1 to 3. FIG. 4 illustrates expediently such anexample that the number of divided cores 5 is four, which can beextended to any larger number with the same manner.

As shown in the, the divided cores 5 supported by the individual coilwinding frames 6 are made bent at the coupling parts a so that the teethparts 5-1 are directed inward. The envelope developed by the couplingparts a makes a circle C shown by the broken line. In this state, as theengagement parts 5-2 having a narrow width locate outside, the coilwinding 7 can be wound continuously by machine-wound work. At thisprocess, the cylindrical support tool 10 is applied inside the teethparts 5-1 for stabilizing the machine-wound work.

FIG. 5 illustrates interpretatively the formation of the abduction-typestator cores starting from the state as described above. As shown in thefigure, in bending the coupling parts a in the direction opposite to thestate shown in FIG. 4, the teeth pars 5-1 of the divided cores 5 faceoutward to the circle C shown by the broken like, and then, the circle Cdeveloped by the engagement parts 5-2 moves inside and the adjacentunits contacts to each other. Then, the stator support members 8 (inFIG. 1) are made inserted and fixed.

As described above, in this embodiment, it will be appreciated that theabduction-type stator cores can be assembled easily.

FIG. 6 shows a cross-section view of the state after the coil winding iscompleted, in which the coil winding work for the individual dividedcores 5 is operated with the coil winding frames 6. The identicalnumbers are assigned to the identical parts to those in FIGS. 1 to 5.

The process for forming the abduction-type stator cores with the dividedcores 5 from this state is the same as the case illustrated by FIGS. 4and 5, and the shape of the abduction-type stator cores is defined, andthen, the stator support member 8 can be fixed by pressing it in theaxial direction, and consequently, the abduction-type stator cores canbe completed.

In order to prevent the interference among the coil windings in theassembly process, it is required that the number of layers (the numberof phase of the coil winding) (the number of layers is 3 in FIG. 6) atthe root of the core (inside part) is larger than the number of layers(the number of layers is 1 in FIG. 6) at the top of the teeth parts 5-1.

In this coil winding method, as the coil winding process is applied withthe top of the teeth part 5-1 being located inside, and as the start andend of the coil winding are located inside the position for the coilwinding operation, that is, located at the top of the teeth part 5-1, itwill be appreciated that the interference among the coil wires can beprevented in the assembly process and the assembly process itself iscompleted easily.

The positions of the start and end of the coil winding in the coilwinding work and the arrangement of the crossover line as well as theirrelationship are described in FIG. 8(a-b) and subsequent figures. FIG.8(a-b) shows the coil winding state in case of the three-phase andten-pole device. FIG. 8(a) illustrates the state of the coil windingwork for the first phase, and FIG. 8(b) illustrates the state of thecoil winding work continued up to the third phase. As shown in FIG. 8 bwith twelve units (5 a to 5 l) of the divided core 5, the teeth parts5-1 are supported by the coil winding frames 6 and arranged on thesupporting member 10 so as to direct to the center. As the coil windingframes 6 between the divided cores 5 a and 5 l discontinues to eachother at the boundary shown by the broken line k, the coil windingframes are fixed by a tool (not shown).

FIG. 8(a-b) is an example of processing the coil winding worksequentially in three phases, A-phase, B-phase and C-phase, and the coilwinding work starts at the coil winding of the divided core 5 a forA-phase. The component 7 in is a lead line for the start of the coilwinding work. Once the coil winding work for the divided core 5 a iscompleted, the coil winding work for the divided core 5 b is initiatednext with its winding direction reversed, in which the crossover linedue to this transition is the component 7 s. After the coil winding workfor the divided core 5 b is completed, the coil winding work for thedivided core 5 g for the A-phase on the diagonal position opposite tothe divided core 5 a is initiated with the crossover line 7 a. Aftercompleting the coil winding work for the divided core 5 g, the coilwinding work for the divided core 5 h adjacent to the divided core 5 gis initiated, and next, the coil winding work for the divided core 5 cfor B-phase is initiated with the crossover line 7 ab. The crossoverline bridging those phases is cut at the position marked with the symbolX and its cable terminals are treated subsequently. As for B-phase, inthe similar manner to A-phase, the coil winding works for the dividedcores 5 c, 5 d, 5 i and 5 j are processed in sequence, and then, thecoil winding works for the divided cores 5 e, 5 f, 5 k and 5 l forC-phase are processed and finally the coil winding works are completedat the lead line 7out. In the result of those coil winding works, sixcrossover lines 7 s bridges the individual adjacent divided cores, andthree crossover lines 7 a, 7 b and 7 c extended longer and a couple ofcrossover lines, 7 ab and 7 bc, bridge the divided cores with differentphases.

Now, suppose that the circle shown in FIG. 8(b) is cut at the brokenline k between the divided cores 5 a and 5 l and that the divided cores5 a and 5 l are made turned over so that the engagement parts 5-2 of thedivided cores may be located inside as shown in FIG. 9(a-c). FIG. 9(a)shows the assembled state of the abduction-type stator, FIG. 9(b) is aperspective view of the assembled stator supported by the stator supportmember, and FIG. 9(d) is a perspective view of the state of the processof inserting the housing.

Note that the hypothetical circle (the circle C drawn in the broken linein FIG. 4 and FIG. 5) defined by connecting the engagement parts a ofthe coil winding frame 6 shown in FIG. 8 holds an identical length (anidentical diameter) at the coil winding work and the assembly process,and that the crossover line of the coil winding 7 after the assemblyprocess has an adequate extended length for a single slot or more incomparison to the coil winding process, not excessive or notinsufficient, which leads to making no obstacle or no shortage forestablishing the state transition from FIG. 8 to FIG. 9. This transitioncan be realized by means that the engagement part a composed ofinsulation material which enables on part of the coil winding frame 6 tobend flexibly is formed near the teeth part 5-1 from the center of thedivided core 5. After the transition to the state shown in FIG. 9, thedivided core 5 is made fixed by inserting the housing 9 and then theassembly process for the stator is completed.

FIG. 10 shows an example of the structure of the motor having the abovedescribed stator core structure. The bearing 28 is arranged with thecurler 29 in the inside of the housing 9 which is fixed firmly in thestator core 5 having the coil winding (coil) 7, and then the motor shaft25 is arranged. The cup-shaped stator case 16 is coupled together at theend part of the shaft 25, and the rotor 1 is arranged by any bondingmethod at the inside of the rotor case 16 facing to the stator core 5.The bonding between the base part 26 of the motor and the housing 9 isfixed by press fitting, screw fastening, shrinkage fitting or welding,and then the control board 27 is made arranged between the stator andthe base.

According to this structure, it will be appreciated that a low-cost,compact, high-torque and high-efficiency motor can be obtained.

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

1. A method of assembling a stator of an abduction-type motor having adivided core formed by dividing a stator core into plural blocks withits teeth top parts arranged in a direction to outside and structured asbeing reassembled with said divided cores, said method comprising;forming a coil winding frame as a series of units, each unit coupled atcoupling parts made of insulation material and embedded into saidindividual divided core, a part of which can be flexibly bended;embedding said coil winding frame into each of said divided cores;performing coil winding whereby coupling parts of said coil windingframe are deformed and arranged during said coil winding so that teethtop parts of said divided core are arranged in a circular arrangementand directed inward; and continuously performing coil winding on saiddivided cores, wherein coupling parts of said coil winding frame aredeformed after completion of said coil winding so that teeth parts ofsaid divided core are directed outward.
 2. The assembling method of astator of an abduction-type motor of claim 1, wherein said coil windingframe formed as a series of units, each coupled at coupling parts madeof insulation material, a part of which can be flexibly bended, isdivided into two parts in an axial direction and each of said units isembedded into said divided core.
 3. The assembling method of a stator ofan abduction-type motor of claim 1, wherein said coil winding frameformed as a series of units, each coupled at coupling parts made ofinsulation material, a part of which can be flexibly bended, isintegrally formed with said divided core by insert molding.
 4. Theassembling method of a stator of an abduction-type motor of claim 1,wherein teeth parts of said divided cores are so assembled and fixed soas to be directed outward and located on a circle so that coupling partsof said coil winding frame, a part of which can be flexibly bended andmade of insulation material are located in a circular arrangement. 5.The assembling method of a stator of an abduction-type motor of claim 1,wherein coupling parts of said coil winding frame, a part of which canbe flexibly bent and made of insulation material, are placed at aposition shifted from a center of said divided core and closer to teethtop parts.
 6. The assembling method of a stator of an abduction-typemotor of claim 1, wherein said divided cores are arranged so that teethtop parts of said divided cores are directed inward, and a continuouscoil winding work is applied for an individual phase by using a statorcore coil winding apparatus.
 7. An abduction motor comprising dividedcores, coil winding frames embedded into the teeth parts of said dividedcores, and a coil winding wound around said coil winding frames, whereinsaid coil winding frames are coupled by a coupling part able to be bent,and wherein lead lines for the start of a coil winding and the end ofthe coil winding are arranged at a top portion of said teeth parts.